PHONG NA (VIETNAM) — Securing a spot to visit the world’s biggest cave is like getting tickets to a Jacky Cheung concert, only harder.

So, I was lucky to have gotten myself on the “guest list” to Vietnam’s otherworldly Hang Son Doong cave, a natural wonder estimated to be three million years old.

Hang Son Doong, which means “Mountain River Cave”, is part of the subterranean labyrinth of limestone caverns that placed the Phong Nha-Ke Bang National Park on Unesco’s World Heritage Sites list. The cave remained unexplored until 2009, when it was unveiled as the largest cave passage in the world. It is so big, it has its own river, jungle and weather system.

Oh, and you have to abseil into it.

To preserve its pristine state, a very limited number of visitor permits are issued annually. Up until last year when I visited, that number was 500. This year, it is 800 for the season — which falls between the months of February and August.

Even though tours cost US$3,000 (S$4,212) a spot, there is no shortage of demand. Rumours abound of property developers’ plans to build golf courses all over the National Park — complete with cable cars, boardwalks and fairy lights — and threatening certain wreckage of the cave network’s fragile ecology.

So, tour spaces for the entire caving season are snapped up within hours of their release. The spots for this year, needless to say, are sold out, but it is not too early to get on the mailing list for 2018.

At any one time, a group of 10 tourists enters the cave for five days and four nights to touch the back of the cave and return.

It is an exceptional experience in the wilderness — with only a 30-man supporting contingent of guides, porters and cooks for company.

I had never gone caving before, but I was looking forward to the quiet of Hang Son Doong as a tonic for the frenzy of Singapore.

OF TREKKING, DRINKING AND A CINDERELLA MOMENT

To get there, I flew to Dong Hoi via Ho Chi Minh City, where I was picked up by the tour operator and transported to Phong Nga.

The adventure began slowly, with hours of walking through jungles towards the cave.

Bashing through tall grass in hot and sticky conditions brought back memories of Tekong Island. But unlike Tekong, we would enter clearings where picnic baskets of banh mi (Vietnamese baguette sandwiches) would be laid out and waiting for us.

By mid-afternoon, we were at the intermediate cave that was to house our first campsite: Hang En, the world’s third-largest cave.

Clambering up a final ridge, we looked down and were blown away by a view of sandy shores by a cave lake. We swam, ate and started drinking.

Vietnamese rice wine, transported in reused mineral water bottles, is unexpectedly potent. Some time after dinner, a guide found me kneeling down, clutching handfuls of sand and searching for a lost flip-flop.

On the way back from the camp toilet (a composting bucket fitted with a Western-style seat), my foot had plunged into the dunes and the sands had swallowed my slipper.

The guide coolly assessed the situation, stepped forward and pulled out the missing footwear, before hauling me back to the campsite.

CINEMATIC VIEWS, FINAL DESCENTS

The second day was spent traversing an idyllic river valley. We waded through the river and watched butterflies chase one another. We also listened to the guides’ gossip about which visiting celebrity was a prima donna, since those caves and valleys had served as film locations for several movies including Pan and the upcoming Kong: Skull Island.

Just after lunch, we arrived at Hang Son Doong. Gazing into the unending darkness, we were greeted by clouds of water vapour rolling out periodically. Then, turning on our headlamps, we strapped ourselves into harnesses and abseiled down into the cave.

The descent was the most challenging part of our expedition. After that, we were required to walk in the dark and cross a few underground streams in complete darkness.

After dinner at the campsite, we sat around a fire trying to dry our sodden footwear held above the flames on sticks, cautiously sipping rice wine and telling one another stories about our previous adventures.

I was the only Singaporean in my group of 10 travellers, for which I was glad, since I had come to escape from well, people in general.

But I was starting to find out that I was part of an extraordinary group consisting of a Canadian grandmother who was an avid trekker, an American nurse engaged in global relief efforts, a Brit who had been on the Queen’s New Years’ honours list for international development work, and three Vietnamese excited to discover one of their national treasures. Every one of them was a nature lover with a social activist streak.

I learned that the gift of the cave was not solitude, but intimacy — it provided the space for like-minded people to find and enjoy one another.

CAVE FAMILY MOMENTS

The next day’s trek to our third camp was the most harrowing part of the trip, but also the most spectacular.

Walking through areas where the cave ceiling had fallen in meant clambering into tunnels of rockfall and squeezing through narrow, slippery passages. But it also meant emerging into unspoiled cave forests, scrambling up massive stalagmites in order to pretend I was in a Kindle advertisement, and taking advantage of a circular human-sized passage to strike James Bond poses in.

After lunch at Camp 3, we set out for the end of the cave, a giant mud wall called the “Great Wall of Vietnam”. I had announced that I would not venture in all the way because I knew it would be muddy and there was no water near Camp 3 to wash with.

Unfortunately, three days with my group had built an irresistible fellowship, and I submitted to peer pressure and trudged on. So, I stood at the Great Wall of Vietnam with mud splattered all over my trousers. I pressed my palm to the wall, then promptly slipped and tumbled down a mud slope, to everyone’s sadistic delight.

I spent an evening caked in mud, playing cards by the light of head-torches, performing charades with shadows cast on the cave walls and, of course, more drinking with my cave family. At midnight, a few of us sat around in silence together, looking up at the stars. We knew that we would have only one more night together before we emerged from the cave.

At the end of a two-day trek, we each received a medal proclaiming: “You Have Conquered Son Doong, The World’s Largest Cave.” Needless to say, a disc on a ribbon as a souvenir of my trip was not necessary.

Those were exhilarating days of walking through natural beauty and relaxing nights of absorbing conversations, and they gave me more than what I expected.

I had entered Hang Son Doong for the solitude, but exited with friends.

For information on the Hang Son Doong tour, visit oxalis.com.vn